Together with the mother, her two daughters were also offered to me – under an unfavourable omen, if an offence to probity can be interpreted as such: for the project was presented by the well-wishers of the ladies in a form which was not very proper. The ugliness of this project upset me intensely; yet I began nevertheless to inquire into the conditions. As I thus transferred my interest from widows to virgins, and continued to think of the absent one [the mother] whom, so far, I had not seen, I was captivated by the appearance and pleasant features of the one who was present [the daughter]. Her education had been, as it became sufficiently clear, more splendid than it would be useful to me. She had been brought up in luxury that was above her station, also she was not of sufficient age to run a household. I decided to submit the reasons which spoke against the marriage to the judgment of the mother, who was a wise woman and loved her daughter. But it would have been better if I had not done so, because the mother did not seem to be pleased. This was the second one, and now I come to the third."
The third was a maiden in Bohemia whom Kepler found attractive, and who took a liking to his orphaned children. He left them for a while in her care "which was a rash act, for later on I had to fetch them back at my own expense". She was willing to marry him, but she had, a year earlier, given her word to another man. That other man had, in the meantime, begotten a child with a prostitute, so that the maiden considered herself free; but she thought it nevertheless necessary to obtain the permission of her ex-fiancé's employer. This employer had some time ago given Kepler a letter of recommendation – and by a mysterious non-sequitur, Kepler states that this prevented the marriage. We are left to wonder.
The fourth he would have married gladly, in spite of her "tall stature and athletic build", if meanwhile the fifth had not entered the scene. The fifth was Susanna, his future wife:
"In comparing her to the fourth the advantage was with the latter as regards the reputation of the family, earnestness of expression, property and dowry; but the fifth had the advantage through her love, and her promise to be modest, thrifty, diligent and to love her step-children... While I was waging my long and heavy battle with this problem, I was waiting for the visit of Frau Helmhard, wondering whether she would advise me to marry the third, who would then carry the day over the last-mentioned two. Having at last heard what this woman had to say, I began to decide in favour of the fourth, annoyed that I had to let the fifth go. As I was turning this over, and on the point of making a decision, fate intervened: the fourth got tired of my hesitations and gave her word to another suitor. Just as I had been previously annoyed about having to reject the fifth, I was now so much hurt about the loss of the fourth, that the fifth too began to lose her attraction for me. In this case, to be sure, the fault was in my feelings.
Concerning the fifth, there is also the question why, since she was destined for me, God permitted that in the course of one year, she should have six more rivals? Was there no other way for my uneasy heart to be content with its fate than by realizing the impossibility of the fulfilment of so many other desires?"
And so to No. 6, who had been recommended to Kepler by his step-daughter:
"A certain nobility, and some possessions made her desirable; on the other hand, she was not old enough, and I feared the expense of a sumptuous wedding; and her noble rank in itself made her suspect of pride. In addition, I felt pity for the fifth, who had already understood what was afoot and what had been decided. This division in me between willingness and unwillingness had, on the one hand, the advantage that it excused me in the eyes of my advisers, but on the other the disadvantage that I was as pained as if I had been rejected... But in this case too, Divine Providence had meant well because that woman would not have fitted in at all with my habits and household.
Now, as the fifth ruled, to my joy, alone in my heart, a fact which I also expressed to her in words, suddenly a new rival arose for her, whom I shall call No. 7 – because certain people, whom you know, suspected the humility of the fifth and recommended the noble rank of the seventh. She also had an appearance which deserved to be loved. Again I was prepared to give up the fifth, and to choose the seventh, provided it was true what they said about her..."
But again he prevaricated;
"and what else could have been the result but a rejection, which I had quasi-provoked?"
Tongues were wagging all over Linz; to avoid more gossip and ridicule, he now turned his attention to a candidate of common origin "who nevertheless aspired to the nobility. Though her appearance had nothing to recommend her, her mother was a most worthy person." But she was as fickle as he was undecided, and after alternately giving him her word and retracting it on seven subsequent occasions, he again thanked Divine Providence and let her go.
His methods now became more cautious and secretive. When he met No. 9, who, apart from a lung disease, had much to recommend her, he pretended to be in love with somebody else, hoping that the candidate's reactions might betray her feelings. Her reactions were promptly to tell Mother, who was ready to give her blessing, but Kepler mistakenly thought she had rejected him and then it was too late to put matters right.
The tenth was also of noble rank, of sufficient means and thrifty.
"But her features were most abhorrent, and her shape ugly even for a man of simple tastes. The contrast of our bodies was most conspicuous: I thin, dried-up and meagre; she, short and fat, and coming from a family distinguished by redundant obesity. She was quite unworthy to be compared with the fifth, but this did not revive love for the latter."
The eleventh and last one was again "of noble rank, opulent and thrifty"; but after waiting four months for an answer, Kepler was told that the maiden was not yet sufficiently grown up.
"Having thus exhausted the counsels of all my friends, I, at the last moment before my departure for Rattisbon, returned to the fifth, pledged her my word and received hers.
Now you have my commentary on my remark at the beginning of this invitation. You now see how Divine Providence drove me into these perplexities that I may learn to scorn noble rank, wealth and parentage, of which she has none, and to seek with equanimity other, simpler virtues..."
The letter ends with Kepler entreating his aristocratic friend to come to the wedding banquet and help him by his presence to brave the adversity of public opinion.
Susanna seemed to have justified Kepler's choice, and lived up to his expectations. There is hardly any later mention of her in his letters, and as far as Kepler's domestic life was concerned, no news is good news. She bore him seven children, of whom three died in infancy.
I have said, at the beginning of this chapter, that Kepler's way of discovering the right wife for himself strangely reminds one of the method of his scientific discoveries. Perhaps, at the end of this matrimonial odyssey, this sounds less far-fetched or whimsical. There is the same characteristic split in the personality between, on the one hand, the pathetically eager, Chaplinesque figure who stumbles from one wrong hypothesis to another and from one candidate to the next – oval orbits, egg-shaped orbits, chubby-faced orbits; who proceeds by trial and error, falls into grotesque traps, analyses with pedantic seriousness each mistake and finds in each a sign of Divine Providence; one can hardly imagine a more painfully humourless performance. But on the other hand, he did discover his Laws and did make the right choice among the eleven candidates, guided by that sleepwalking intuition which made his waking errors cancel out and always asserted itself at the critical moment. Social rank and financial considerations are topmost in his waking consciousness, yet in the end he married the only candidate who had neither rank, nor money, nor family; and though he anxiously listens to everybody's advice, seems to be easily swayed and without a will of his own, he decides on the person unanimously rejected by all.
It is the same dichotomy which we observed in all his activities and attitudes. In his quarrels with Tycho and constant naggings at him, he displayed embarrassing pettiness. Yet he was curiously devoid
of jealousy or lasting resentment. He was proud of his discoveries and often boasted of them (particularly of those which turned out to be worthless), but he had no proprietary feeling about them; he was quite prepared to share the copyright of the three Laws with the Junker Tengnagel and, contrary to the habits of the time, gave in all his books most generous credit to others – to Maestlin, Brahe, Gilbert and Galileo. He even gave credit where none was due, for instance to Fabricius, whom he nearly saddled with the honour of having discovered the elliptic orbits. He freely informed his correspondents of his latest researches and naïvely expected other astronomers to part with their jealously guarded observations; when they refused, as Tycho and his heirs did, he simply pinched the material without a qualm of conscience. He had, in fact, no sense of private property concerning scientific research. Such an attitude is most unusual among scholars in our day; in Kepler's day it seemed quite insane. But it was the most endearing lunacy in his discordant, fantastic self.
XI THE LAST YEARS
1. Tabulae Rudolphinae
ARMONICE MUNDI was completed in 1618 and published the next year, when Kepler was forty-eight. His pioneering work was done; but in the remaining eleven years of his life he continued to pour out books and pamphlets – annual calendars and ephemerides, a book on comets, another on the new invention of logarithms, and two more major works: the Epitome Astronomiae Copernicanae and the Rudolphine Tables.
The title of the former is misleading. The Epitome is not an abstract of the Copernican system, but a textbook of the Keplerian system. The laws which originally referred to Mars only, are here extended to all planets, including the moon and the satellites of Jupiter. The epicycles are all gone, and the solar system emerges in essentially the same shape in which it appears in modern school-books. It was Kepler's most voluminous work and the most important systematic exposition of astronomy since Ptolemy's Almagest. The fact that his discoveries are found in it once more side by side with his fantasies, does not detract from its value. It is precisely this overlapping of two universes of thought, which gives the Epitome, as it does to the whole of Kepler's life and work, its unique value to the history of ideas.
To realize how far ahead of his colleagues Kepler was, in spite of the residue of medievalism in his veins, one must compare the Epitome with other contemporary textbooks. None of them had adopted the heliocentric idea, or was to do so for a generation to come. Maestlin published a reprint of his textbook based on Ptolemy in 1624, three years after the Epitome; and Galileo famous Dialogue on the Great Systems of the World, published another eight years later, still holds fast to cycles and epicycles as the only conceivable form of heavenly motion.
The second major work of Kepler's late years was his crowning achievement in practical astronomy: the long-awaited Rudolphine Tables, based on Tycho's lifelong labours. Their completion had been delayed for nearly thirty years by Tycho's death, the quarrel with the heirs, and the chaotic conditions created by the war – but basically by Kepler's reluctance against what one might call a Herculean donkey-work. Astronomers and navigators, calendar-makers and horoscope-casters were impatiently waiting for the promised Tables, and angry complaints about the delay came from as far as India and the Jesuit missionaries in China. When a Venetian correspondent joined in the chorus, Kepler answered with a cri de cœur:
"One cannot do everything, as the saying goes. I am unable to work in an orderly manner, to stick to a time schedule and to rules. If I put out something that looks tidy, it has been worked over ten times. Often I am held up for a long time by a computing error committed in haste. But I could pour out an infinity of ideas... I beseech thee, my friends, do not sentence me entirely to the treadmill of mathematical computations, and leave me time for philosophical speculations which are my only delight." 1
At last, when he had turned the corner of fifty, he really settled down to the task at which he had only nibbled since Tycho's death. In December 1623, he triumphantly reported to an English correspondent: video portum – "I can see the harbour"; and six months later to a friend: "The Rudolphine Tables, sired by Tycho Brahe, I have carried in me for twenty-two years, as the seed is gradually developed in the mother's womb. Now I am tortured by the labours of birth." 2
But owing to lack of money and the chaos of the Thirty Years War, the printing took no less than four years, and consumed half of his remaining energies and life-span.
Since the Tables were to bear Rudolph's name, Kepler found it fitting that the printing should be financed by payment of the arrears due to him, amounting to 6,299 florins. He travelled to Vienna, the new seat of the Imperial Court, where he had to spend four months to obtain satisfaction. But the satisfaction was of a rather abstract nature. According to the complicated method by which the Crown's financial affairs were transacted, the Treasury transferred the debt to the three towns of Nuremberg, Memmingen and Kempten. Kepler had to travel from town to town – partly on horseback, partly on foot because of his piles; and to beg, cajole and threaten, until he finally obtained a total of 2,000 florins. He used them to buy the paper for the book, and decided to finance the printing out of his own pocket, "undaunted by any fear for the future sustenance of wife and six children", and though he was forced "to dip into the money held in trust for the children from my first marriage". He had lost a whole year on these travels.
But this was only the beginning of his struggles; the story of the printing of the Rudolphine Tables reminds one of the Ten Egyptian Plagues. To begin with, Linz did not have an adequate printing press for such a major undertaking; so Kepler had to travel again to recruit skilled printers from other towns. When the work at last got going, the next plague descended – a familiar one this time: all Protestants in Linz were ordered either to embrace the Catholic faith, or to leave the town within six months. Kepler was again exempted, and so was his Lutheran master printer with his men; but he was requested to hand over to the authorities all books suspect of heresy. Luckily, the choice of objectionable books was left to his own judgment (which made him feel "as if a bitch were asked to surrender one of her litter") and, thanks to the intervention of the Jesuit Father Guldin, he was able to keep them all. When the war was approaching Linz, the authorities asked Kepler's advice how to protect the books of the Provincial Library against the danger of fire; he recommended packing them tightly into wine barrels so that they could easily be rolled away from the danger spot. Incidentally, notwithstanding his excommunication (now final), Kepler kept paying visits to his beloved Tuebingen, the Lutheran stronghold, and having a jolly time with old Maestlin – all of which goes to show that the sacred cows of that bygone Age of Humanism were still held in respect during the Thirty Years War, both in Germany and Italy, as the case of Galileo will show.
The third plague was the garrisoning of Linz by Bavarian soldiery. Soldiers were billeted everywhere, even on Kepler's printing shop. This led to a rumour which spread through the Republic of Letters, and penetrated as far as Danzig, that the soldiers had melted down Kepler's lead type to make bullets, and pulped his manuscripts for use as cartridge cases – but luckily this was not true.
Next, the Lutheran peasantry rose in bloody revolt, burnt down monasteries and castles, occupied the township of Wels and laid siege on Linz. The siege lasted for two months, June-August 1626. There were the usual epidemics, and the populace was reduced to living on horse-flesh, but Kepler "by the help of God and the protection of my angels" was preserved from this fate.
"You ask me," he wrote to Father Guldin, "what I did with myself during the long siege. You ought to ask what one could do in the midst of the soldiery. The other houses had only a few soldiers billeted on them. Ours is on the city wall. The whole time the soldiers were on the ramparts, a whole cohort lay in our building. The ears were constantly assailed by the noise of the cannon, the nose by evil fumes, the eye by flames. All doors had to be kept open for the soldiers who, by their comings and goings, disturbed sleep at night, and work during day-time. I nevertheless cons
idered it a great boon that the head of the Estates had given me rooms with a view over the moats and suburbs in which the fighting took place." 3
When he did not watch the fighting, Kepler, in his unquiet study, was engaged with his old occupational therapy, the writing of a chronological work.
On 30 June, however, the peasants succeeded in setting fire to part of the town. It destroyed seventy houses, and among these was the printing shop. All the sheets that had so far been printed, went up in flame; but the angels again intervened and Kepler's manuscript escaped unscathed. This provided him with an occasion for one of his endearing understatements: "It is a strange fate which causes these delays all the time. New incidents keep occurring which are not at all my fault." 4
Actually, he was not too much aggrieved by the destruction of the printing press, because he had had more than enough of Linz, and was only waiting for a pretext to move elsewhere. He knew of a good press in Ulm, on the upper reaches of the Danube, which belonged to his Swabian homeland, and was less than fifty miles from Tuebingen – that magnetic pole which never lost its attraction. When the siege was lifted and the Emperor's consent obtained, Kepler was able, after fourteen long years, to leave Linz, which he had never liked, and which had never liked him.